A practical approach for enhanced biodiesel production using organic modified montmorillonites as efficient heterogeneous hybrid catalysts

Developing efficient and environmentally friendly heterogeneous catalysts for sustainable biodiesel preparation is considered a viable manner to meet global energy demand and alleviate environmental concerns. In this work, a series of novel mesoporous organic-inorganic hybrid clay materials ILs-OMt-x (x, the use of pyrrole mass, x = 0.4, 0.6, and 0.8 g), were fabricated by pyrrole in situ polymerization utilizing ionic liquid (IL)-grafted biocompatible montmorillonite (Mt) as a modified matrix under relatively mild conditions. Among these clay materials, it was determined that ILs-OMt-0.6 had favorable physicochemical properties, including large specific surface area (SBET, 80.41 m2 g-1), layered mesoporous structure (12.28 nm), multiple acid sites, and relatively strong acid intensity (1.63 mmol g-1). As a result, ILs-OMt-0.6 showed outstanding catalytic performance in biodiesel preparation, and the highest biodiesel yield of 97.02% was obtained after single-factor and response surface methodology (RSM) optimization (6.4 wt% catalyst dosage, 15.2 : 1 molar ratio of methanol to oleic acid (OA), 6.3 h, 83.0 degrees C). In addition, kinetics study further confirmed its lower activation energy compared with pristine Mt and commercial resin Amberlyst-15, and a possible esterification mechanism was also proposed. Importantly, ILs-OMt-0.6 showed excellent substrate versatility, displaying satisfactory catalytic performance in trans(esterification) of other fatty acids and raw non-edible oils. It is worth mentioning that the physicochemical properties of as-synthesized biodiesel conformed with international standards, and its life-cycle cost (LCC) indicated the good economic viability of ILs-OMt-0.6 for efficient catalytic biodiesel production. This study reveals a promising application path of novel hybrid materials with favorable physicochemical properties in biodiesel production and provides new paths for fabricating Mt-based catalysts with high efficiency and stability for the sustainable development of liquid biomass refining technology. Developing efficient and environmentally friendly heterogeneous catalysts for sustainable biodiesel preparation is considered a viable manner to meet global energy demand and alleviate environmental concerns.